The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that defines a process for the automated assignment of available routers to participating hosts. This process improves the availability and reliability of routing paths via automatic gateway selections on an Internet Protocol (IP) subnetwork.
VRRP defines a virtual router, which can be implemented by any one of a set of physical routers. The physical routers can be classified as a master router and a set of backup routers. VRRP assigns a participating host to a gateway that is a virtual router rather than a physical router. If the physical router implementing the virtual router fails, another physical router (i.e., one of the set of backup routers) is automatically selected to take over the execution of the virtual router. The physical router that is implementing the virtual router and forwarding packets at any given time is called the master router.
VRRP provides information on the state of a router, not the routes processed and exchanged by that router. Each VRRP instance is limited, in scope, to a single subnet (e.g., a local area network). VRRP does not advertise routes beyond that subnet or affect the routing outside the subnet. VRRP can be used with Ethernet, multi-protocol label switching (MPLS), and token ring networks. VRRP is described in IETF publication RFC 5798.